The Middlesex District Attorney says a 43-year-old man was shot and killed by police in Reading.
Authorities didn't immediately release the man's name.
The district attorney's office says Reading Police responded to a residence on Main Street for a report of an alleged assault involving the man and a household member Saturday.
Officers had responded to the same home Friday for a reported altercation involving the same man, who fled before they arrived.
The office says when police arrived Saturday, the man fled again. A Reading officer found him and fired.
The man was pronounced dead at a nearby hospital. The officer was treated and released.
The office didn't say why the officer shot the man or how the officer was injured.
It says the circumstances are under investigation.